KDE uses a common repository to store our Source Code and to track changes made to the code. Currently, KDE is in the middle of migrating our main repository from Subversion (SVN) to Git, so some software modules will be downloaded from Git and some from Subversion. This means you will need to become familiar with both systems.
For more information on using Git in KDE, please see the KDE Git page.
For more information on using Subversion, please see the following pages which may be outdated with regards to which modules live in SVN: